1. Technical Field
This disclosure relates to an image forming apparatus, and more specifically to an image forming apparatus having a carriage mounting a recording head for ejecting liquid droplets.
2. Description of the Related Art
Image forming apparatuses are used as printers, facsimile machines, copiers, plotters, or multi-functional devices having two or more of the foregoing capabilities. As one type of image forming apparatus employing a liquid-ejection recording method, for example, an inkjet recording apparatus is known that uses a recording head (liquid ejection head or liquid-droplet ejection head) for ejecting droplets of ink.
Such a liquid-ejection-type image forming apparatus may have a maintenance device (maintenance-and-recovery device) to maintain and recover the ejection stability of nozzles of the recording head. The maintenance device includes, for example, a suction cap to cap a nozzle face of the recording head for sucking and discharging liquid from the nozzles, a moisture retention cap to prevent drying of ink in the nozzles and incorporation of dust into the nozzles, and a wiper member (also referred to as wiper blade, wiping blade, or blade) to wipe and clean the nozzle face of the recording head. The maintenance device performs, for example, recovery operation to form nozzle menisci by wiping the nozzle face by the wiping member after viscosity-increased ink is discharged from the nozzles to the suction cap.
As a conventional type of maintenance device, for example, JP-09-300644-A proposes a maintenance device movable in a sub-scanning direction perpendicular to a main scanning direction between a maintenance position at which the maintenance device opposes the recording head mounted on the carriage to perform maintenance and recovery operation and a retreat position at which the maintenance device does not oppose the recording head.
To enhance the productivity, in an image forming apparatus, recording heads for ejecting the same color of liquid droplets are arranged in an offset manner so as to be placed at different positions in the sub-scanning direction, thus increasing the printing width of the recording heads in the sub-scanning direction at which the recording heads can print an image by a single main scanning operation. For the image forming apparatus, a maintenance device includes maintenance units arranged so that the respective recording heads displaced in the sub-scanning direction can oppose the corresponding maintenance units.
Such a configuration increases the number of components of the maintenance device and the space in the main scanning direction, thus increasing the width of the apparatus body (the apparatus size in the main scanning direction).